Methods of manufacturing an organic electroluminescent device

ABSTRACT

A manufacturing method for an organic electroluminescent device that includes an effectively optical area including display pixels for display and a dummy area surrounding the effectively optical area, the dummy area including dummy pixels not for display is provided. The manufacturing method includes coating a first composite material on a first portion in the effectively optical area, the first portion corresponding to one of the display pixels, and coating a second composite material separately from the coating of the first composite material, the second composite material being coated on a second portion of the dummy area, the second portion corresponding to one of the dummy pixels, the first composite material including a first organic electroluminescent material that is dissolved or dispersed in a solvent and the second composite material including a second organic electroluminescent material that is dissolved or dispersed in a solvent.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Division of U.S. patent application Ser. No. 13/859,262 filedApr. 9, 2013, which in turn is a Division of U.S. patent applicationSer. No. 12/219,834 filed Jul. 29, 2008 (now U.S. Pat. No. 8,454,403),which is a Continuation of U.S. patent application Ser. No. 11/176,249filed Jul. 8, 2005 (now U.S. Pat. No. 7,755,277), which is a Division ofU.S. patent application Ser. No. 10/786,060 filed Feb. 26, 2004 (nowU.S. Pat. No. 6,924,593), which is a Division of U.S. patent applicationSer. No. 09/991,984 filed Nov. 26, 2001 (now U.S. Pat. No. 6,784,459).The disclosures of each of the prior applications is hereby incorporatedby reference herein in its entirety

BACKGROUND

The present invention relates to an organic electroluminescent(hereinafter abbreviated as “EL”) device and to a fabrication methodtherefor.

In recent years, development has accelerated with regard to luminouselements that use organic substances as a self-luminous display device.This type of self-luminous display device may supplant conventionalliquid crystal display devices. EL elements that use an organicsubstance as a luminous material can mainly be manufactured by forming amembrane using vapor deposition of an organic EL material (a luminousmaterial) with low molecular weight, as disclosed beginning on page 913of Appl. Phys. Lett. 51 (12), Sep. 21, 1987, and by coating an organicEL material with high molecular weight, as disclosed beginning on page37 of Appl. Phys. Lett. 71 (1), Jul. 7, 1997.

For colorization in the case of a low molecular weight material,respective membranes are formed with various luminous materials whichare vapor-deposited on respective pixels through covering masks. On theother hand, in the case of a high molecular weight material, it has beennotable to realize colorization by a fine patterning using an ink-jetmethod. Fabrication methods of EL elements using an ink-jet method aredisclosed in JP-H7-235378A1, JP-H10-12377A1, JP-H10-153967A1,JP-H11-40358A1, JP-H11-54270A1, JP-H11-339957A1, and U.S. Pat. No.6,087,196B1.

SUMMARY

A super fine patterning of an EL material can be realized by an ink-jetmethod because it is possible to eject droplets having a diameter of afew micrometers in a high resolution manner and to form a coatingtherewith. On the other hand, the minute droplets coated on a substratetend to dry in an extremely short period, and they dry even faster atedge portions (e.g., upper edge, lower edge, right edge, and left edge)of the coated area on the substrate where the partial pressure of thevapor from the minute droplets coated on a pixel area is relatively low.In addition, in the case in which the EL elements are to be activelydriven by TFT (thin-film transistor) elements in use, pixels may not beallowed to be evenly disposed in both X and Y directions due to the TFTelements and the shape and disposition of electric wires, and thepartial pressure of the vapor may vary locally around the droplet coatedon each of the pixels. The time difference in the drying period for theliquid organic material coated on the pixels thus produced may causeuneven thickness of the organic membrane within a pixel or among aplurality of pixels. The uneven thickness of the membrane, in turn, maycause uneven displaying performance, such as uneven luminance, unevenchrominance, etc.

Based on the above description, an object of the present invention is toprovide an enhanced fabrication method for an organic EL device thatincludes ejecting and coating an organic EL material on electrodes toform an organic EL layer, with which uniform physical conditions anddrying period for the liquid EL material coated on a pixel area can berealized, and a uniform organic EL device without uneven luminance anduneven chrominance within a pixel or among a plurality of pixels in aneffectively optical area can be obtained. It is also an object of theinvention to provide such an organic EL device manufactured inaccordance with the above method.

The present invention provides a method for manufacturing an organic ELdevice by coating a composition including an organic EL material above aplurality of electrodes to form an organic EL layer above each of theelectrodes. The method includes: defining an effectively optical area inwhich the plurality of electrodes are formed; and defining a coatingarea being broader than the effectively optical area, in which thecomposition including an organic EL material is to be coated.

According to the above fabrication method, uniform physical conditionsnear the liquid EL material coated on the effectively optical area anduniform drying period for the EL material can be realized in theeffectively optical area, and consequently a uniform thickness of thelayer within a pixel or among a plurality of pixels can be obtained. Anorganic EL layer herein referred to includes a variety of layerscontributing to a luminous effect, such as a hole-injection layer, aluminous layer, and an electron-injection layer. An effectively opticalarea herein refers to an area for the display pixels when the organic ELdevice is a display device, and refers to an area contributing tolighting when the organic EL device is a lighting equipment.

In a method for manufacturing an organic EL device according to thepresent invention, the coating area preferably includes the perimeter ofthe effectively optical area.

According to this method, the drying period for droplets on the pixelslocated near edges of the effectively optical area being much shorterthan that for droplets on the pixels located inside the effectivelyoptical area is avoided. Thus, a uniform thickness of the layer among aplurality of effectively optical pixels can be obtained.

In another method for manufacturing an organic EL device according tothe present invention, the coating area located along the perimeter ofthe effectively optical area is preferably a dummy area in which theorganic EL material solution is also coated to form an organic ELmembrane layer.

Preferably, the method further includes: forming a layer that is made ofthe same material as that of the electrodes in the dummy area; andcoating the composition including an organic EL material on the layer.

According to the above method, uniform physical conditions near theliquid EL material coated on the pixels can be realized even for thepixels located near the edges of the effectively optical area, and thedrying period for droplets on the pixels located near the edges of theeffectively optical area being much shorter than that for droplets onthe pixels located inside the effectively optical area is avoided. Thus,a uniform thickness of the EL membrane layer among a plurality of pixelscan be obtained.

Another method for manufacturing an organic EL device according to thepresent invention preferably includes: providing a group of effectivelyoptical areas formed of a plurality of the effectively optical areas ona substrate; and defining dummy areas around the effectively opticalareas, respectively, and another dummy area encompassing the group ofeffectively optical areas.

A dummy area herein refers to an area relating to neither display norlighting. Therefore, the organic EL layer formed in a dummy area doesnot have to be illuminable, but may be slightly illuminable as long asthis does not interfere with either display or lighting.

According to the above method, uniform physical conditions near theliquid EL material coated on the pixels located near the edges of theeffectively optical area can be realized like for other pixels, and thedrying period for droplets on the pixels located near the edges of theeffectively optical area being much shorter than that for droplets onthe pixels located inside the effectively optical area is avoided. Thus,a uniform thickness of the EL membrane layer among a plurality of pixelscan be obtained, even when a plurality of the effectively optical areasare formed on a substrate, each of which is separated from others, inthe final manufacturing process, to fabricate a plurality of EL devices.In this way, a plurality of EL devices without uneven luminance anduneven chrominance within a pixel or among a plurality of pixels can bemanufactured from a substrate at one time.

In another method for manufacturing an organic EL device according tothe present invention, a process of coating of the composition includingan organic EL material is preferably started at the dummy area prior tocoating on the effectively optical area and ends at the dummy area aftercoating on the effectively optical area.

According to this method, since the process of coating of the organic ELmaterial solution is started at the dummy area and ends at the dummyarea, the coating for effectively optical areas in between can beperformed in a stable condition.

In another method for manufacturing an organic EL device according tothe present invention, individual areas to be coated in the entirety ofthe coating area are preferably disposed with a constant pitch to eachother.

According to this method, uniform physical conditions near the liquid ELmaterial coated on the effectively optical area and uniform dryingperiod for the EL material can be realized in the effectively opticalarea. Consequently, a uniform thickness of the EL membrane layer withina pixel or among a plurality of pixels can be obtained.

In another method for manufacturing an organic EL device according tothe present invention, any one of the electrodes is disposed relative toadjacent ones of the electrodes at a constant pitch. According to thismethod, uniform physical conditions near the liquid EL material coatedon the effectively optical area and uniform drying period for the ELmaterial can be realized in the effectively optical area. Consequently,a uniform thickness of the EL membrane layer within a pixel or among aplurality of pixels can be obtained.

The present invention provides a method for manufacturing an organic ELdevice which includes an effectively optical area having a plurality ofelectrodes and an organic EL layer formed above each of the electrodes.The method includes: forming the organic EL layer both on areas to bethe effectively optical area and on other areas not to be theeffectively optical area.

The present invention provides another method for manufacturing anorganic EL device which includes an effectively optical area having aplurality of electrodes and an organic EL layer formed above each of theelectrodes. The method includes: further forming the organic EL layer inareas not having the electrodes and which are supposed to be theeffectively optical area.

The present invention also provides an organic EL device that ismanufactured by one of the above methods. With such an organic ELdevice, uniform display performance without uneven luminance and unevenchrominance within a pixel or among a plurality of pixels is achieved.

An organic EL device according to the present invention preferablyincludes: a plurality of electrodes and an organic EL layer formed aboveeach of the electrodes; an effectively optical area in which theelectrodes are formed; and a dummy area disposed around the effectivelyoptical area, in which the electrodes are also formed.

Preferably, an organic EL device according to the present inventionfurther includes a bank layer disposed between the electrodes. Theorganic EL layer in the dummy area is disposed on a layer made of thesame material as that of the bank layer.

In an organic EL device according to the present invention, the banklayer preferably includes an organic bank layer and an inorganic banklayer, and the organic EL layer in the dummy area is disposed on a layermade of the same material as that of the inorganic bank layer.

In an organic EL device, the bank layer is preferably disposed laterallybetween portions of the organic EL layer in the dummy area.

In an organic EL device according the present invention, the organic ELlayer in the dummy area is preferably disposed on a layer made of thesame material as that of the organic bank layer.

In an organic EL device of the present invention, the organic EL layerin the dummy area is preferably disposed on a layer made of the samematerial as that of the electrodes.

In an organic EL device of the present invention, the bank layer ispreferably formed laterally between portions of the organic EL layer inthe dummy area.

In an organic EL device of the present invention, adjacent portions ofthe organic EL layer are preferably disposed at a constant pitch in boththe effectively optical area and the dummy area.

In an organic EL device according to the present invention, both theeffectively optical area and the dummy area are preferably provided on asubstrate, and portions in the effectively optical area on the substratehave substantially the same cross-sectional structure as that ofportions in the dummy area on the substrate.

An organic EL device according to the present invention includes aneffectively optical area having a plurality of electrodes and an organicEL layer formed on each of the electrodes, and the organic EL layer isformed both on areas supposed to be the effectively optical area and onother areas not supposed to be the effectively optical area.

An organic EL device according to the present invention includes aneffectively optical area having a plurality of electrodes and an organicEL layer formed above each of the electrodes, and the organic EL layeris also formed in areas not having the electrodes and which are supposedto be the effectively optical area.

The present invention further provides an electronic device includingsuch an organic EL device as described above. With such an electronicdevice, a uniform displaying performance without uneven luminance anduneven chrominance within a pixel or among a plurality of pixels isachieved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing an example of a fabricationmethod for an organic EL device using an ink-jet method;

FIGS. 2A to 2C are cross-sectional views showing an example of afabrication method for an organic EL device using an ink-jet methodrelating to the present invention;

FIGS. 3A to 3D are cross-sectional views illustrating the firstembodiment of the present invention for manufacturing an organic ELdevice;

FIGS. 4A and 4B are cross-sectional views illustrating the secondembodiment of the present invention for manufacturing an organic ELdevice;

FIGS. 5A to 5D are cross-sectional views illustrating the thirdembodiment of the present invention for manufacturing an organic ELdevice;

FIGS. 6A to 6D are cross-sectional views illustrating the fourthembodiment of the present invention for manufacturing an organic ELdevice;

FIGS. 7A to 7D are cross-sectional views illustrating the fifthembodiment of the present invention for manufacturing an organic ELdevice;

FIGS. 8A to 8C are schematics illustrating the sixth-embodiment of thepresent invention for manufacturing an organic EL device;

FIGS. 9A to 9C are schematics illustrating the seventh embodiment of thepresent invention for manufacturing an organic EL device;

FIGS. 10A and 10B are schematics showing the eighth embodiment of thepresent invention for manufacturing an organic EL device; FIG. 10A is aplan view of a substrate before a hole-injection layer is formed, andFIG. 10B is a partial cross-sectional view taken along plane M-M′ inFIG. 10A;

FIGS. 11A and 11B are cross-sectional views illustrating the eighthembodiment of the present invention for manufacturing an organic ELdevice;

FIG. 12 is a plan view of a substrate before a hole-injection layer isformed, illustrating the ninth embodiment of the present invention formanufacturing an organic EL device;

FIGS. 13A and 13B are schematic plan views showing the traced path of anink-jet head, and illustrate the ninth embodiment of the presentinvention for manufacturing an organic EL device;

FIG. 14 is a plan view showing another method for manufacturing anorganic EL device similar to that in the ninth embodiment;

FIGS. 15A to 15C are perspective views of electronic devices accordingto the tenth embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

The preferred embodiments of the present invention will now be explainedwith reference to the drawings, wherein organic EL devices arespecifically formed as display devices.

In a fabrication method for an EL device using an ink jet method, ahole-injection/transportation layer and a luminous material layer areformed by ejecting a composite ink, produced by dissolving or dispersinga hole-injection layer material and a luminous material of pixel-formingorganic substances in a solvent, from an ink jet head, to coat thecomposite ink in a pattern on transparent electrodes. In order toaccurately dispose the ejected ink droplets on predetermined areas ofpixels, a partitioning wall (hereinafter referred to as a “bank”) istypically provided to partition the areas of pixels.

FIG. 1 is a cross-sectional view showing an example of a substratestructure that is included in a method for manufacturing an organic ELdevice using an ink-jet method. A circuit element portion 11′ havingthin-film transistors (TFTs) 11 is formed on a glass substrate 10, andtransparent electrodes 12 made of ITO (Indium Tin Oxide) are formed in apattern on the circuit element portion 11′. In addition, SiO₂ banks 13and organic banks 14 including an ink-repelling organic substance or anorganic substance made to be ink-repelling are laminated on the sectionsthat separate the transparent electrodes 12 to each other. The shape ofapertures defined by the banks may be, for example, circular, oval, orquadrangular; however, in the case of the quadrangular shape, thecorners thereof preferably have a certain curvature since the compositeink inherently has a surface tension. The material of the organic banks14 may be selected from any materials that provide excellent heatresistance, liquid-repellency, resistance ink solvents, and adheringcapability to a base substrate. The material for the organic banks 14 isnot necessarily an inherently liquid-repelling material, such asfluororesin. For example, it may also be a patterned organic resin, suchas acrylic resin, polyimide resin, or the like, as is normally used,whose surface is made liquid-repelling by CF₄ plasma treatment or thelike. Although the banks need not be formed by laminating inorganicsubstances and organic substances, SiO₂ banks 13 are preferably providedin order to enhance adherence to the transparent electrodes 12 when thetransparent electrodes 12 are, for example, made of ITO. A height ofapproximately 1 to 2 micrometers for the organic banks 14 is sufficient.

An example of a fabrication method for an EL device that uses an ink-jetmethod will be explained below with reference to FIGS. 2A to 2C showingeach step of the fabrication process.

As shown in FIG. 2A, a solution including an organic EL material(composite ink) is coated in a pattern on a substrate for pixels usingan ink-jet method to form an organic EL membrane. Composite ink 15 of anorganic EL material is ejected from an ink-jet head 16 and is depositedin a predetermined pattern as shown in FIG. 2B. After coating, thesolvent in the composite ink is removed by a vacuum treatment and/orheat treatment or flow of nitrogen gas or the like to form organic ELmembrane layers 17, as shown in FIG. 2C. The organic EL membrane layers17 are laminated membranes including, for example, a hole-injectionlayer and a luminous layer.

In this process, the solvent of the composite ink dries more quickly onthe display pixels located near the edges of the effectively opticalarea, i.e., an area in which pixels relating to display are formed, thanon the pixels inside the area since ink droplets are not coated aroundthe pixels located near the edges of the area and the partial pressureof the vapor from the ink solvent is lower above the display pixelslocated near the edges of the area than on the pixels inside the area,which may cause thickness variations in the membranes among the displaypixels, as shown FIG. 2C.

In order to uniformly dry droplets coated on each of the pixels, thephysical conditions of respective droplets coated on the effectivelyoptical area are preferably set to be uniform by ejecting and depositingthe composite ink around the effectively optical area as well. Morepreferably, the organic material is coated by an ink-jet method over anarea that is broader than the effectively optical area, whereby a dummyarea, i.e., an area in which dummy pixels not relating to display areformed, including the same bank structure as display pixels, is definedaround the effectively optical area so as to provide physical conditionswhich are as uniform as possible for each of the display pixels.

Individual areas to be coated in the effectively optical area arepreferably disposed at a constant pitch to each other in order toprovide as uniform a drying period for the composite ink as possibleamong the pixels in the effectively optical area. For this purpose, thepixels are preferably disposed at a constant pitch to each other aswell. In the case in which the pitch of the pixels in the X direction isdifferent from that in the Y direction due to disposition of TFTs andbonding wires, ink droplets are preferably ejected in the area betweenthe pixels disposed at a wider pitch so that individual areas to becoated in the entirety of the area for the display pixels are disposedat a constant pitch from each other. More preferably, dummy pixelscomprising the same bank structure as the display pixels are formed inthe area between the pixels disposed at a wider pitch. The shape of thepixels is not limited to a rotationally symmetric shape, such as acircle or a square. For example, it may also be a rectangle, an oval, oran ellipse. When the pixels having the shape of a rectangle or an ovalare disposed at different pitches in the X direction and in the Ydirection, a similar effect can be obtained by providing further areasto be coated in the area between the pixels disposed at a wider pitch sothat the areas to be coated are evenly disposed, although each of theadditional areas to be coated is differently shaped from the displaypixels.

The present invention can not only be applied to a display of an organicEL device, but also to luminous devices and lighting equipment usingorganic EL elements as a light source, for example.

Although the present invention will be more specifically explained belowwith reference to several embodiments, the invention is not limited tothese specific embodiments.

First Embodiment

The substrate used in the first embodiment is a 2-inch TFT substrate inwhich circular pixels having diameters of 30 μm are disposed at a pitchof 70.5 μm in both X and Y directions. This TFT substrate includes aglass substrate 25 and a circuit element portion 26′ having TFTs 26Banned on the glass substrate. FIG. 3A is a partial cross-sectional view(along the X direction) of the right edge portion of the TFT substrate.Transparent electrodes 27 made of ITO are formed on the circuit elementportion 26′ and banks including two layers including SiO₂ banks 28 andpolyimide banks 29 are constructed on the circuit element portion 26′ soas to divide the transparent electrodes 27. The SiO₂ banks 28 aremanufactured in a pattern by photo-etching after forming a 150 nm thickTEOS (tetraethylorthosilicate) layer by CVD (Chemical Vapor Deposition).The polyimide banks 29, which are 2 μm thick, are formed on the SiO₂banks 28 through the steps of coating a photosensitive polyimide on theSiO₂ banks 28, exposure, and development. The material used to form thebanks may be a non-photosensitive substance.

In FIGS. 3A to 3D, the area in which the transparent electrodes 27 areformed is an effectively optical area A and the area in which thetransparent electrodes 27 are not divided by the SiO₂ banks 28, and thepolyimide banks 29 is a dummy area B.

The polyimide banks 29 are made ink-repelling by atmospheric plasmatreatment before applying ink using an inkjet method. The atmosphericplasma treatment that is performed under conditions comprisingatmospheric pressure, a power of 300 W, and 1 mm gap between theelectrodes and the substrate includes an oxygen plasma treatment that isperformed under conditions comprising an oxygen gas flow rate of 100ml/m, a helium gas flow rate of 101/m, and a table speed of 10 mm/s anda consequent CF₄ plasma treatment that is performed under conditionscomprising a CF₄ gas flow rate of 100 ml/m, a helium gas flow rate of101/m, and a reciprocating table speed of 3 mm/s.

Composite ink 30, including Baytron™ supplied by Bayer AG as ahole-injection layer material which is dispersed by a polar solventincluding isopropyl alcohol, N-methylpyrolidone, and1,3-dimethyl-2-imidazolidinone, is ejected from an inkjet head (e.g.,model MJ-930C made by Seiko Epson Corporation) to coat at a pitch of70.5 μm in both the X and Y directions. In this coating process, another30 rows of ejection at the same pitch in both lateral and longitudinaldirections around the display pixels is performed. FIG. 3B is a partialcross-sectional view of the right edge portion of the substrate afterthe composite ink 30 of the hole-injection layer material is coated in apattern. While the composite ink 30 of the hole-injection layer materialis coated on the transparent electrodes 27 in the effectively opticalarea A, the composite ink 30 of the hole-injection layer material iscoated on the polyimide banks 29 in the dummy area B.

Consequently, the solvent is removed by a treatment at room temperaturein a vacuum (1 Torr (133.3 Pa)) for 20 minutes, and then ahole-injection layer 31 is formed, as shown in FIG. 3C, by heattreatment at 200° C. (on a hot plate) in nitrogen gas for 20 minutes.The hole-injection layer 31 having a uniform thickness can thus bemanufactured in the effectively optical area A.

In the next process, three kinds of composite inks, i.e., a compositeink 32 for a red luminous layer, a composite ink 33 for a green luminouslayer, and a composite ink 34 for a blue luminous layer, are preparedusing polyfluorene materials to form luminous layers emitting red,green, and blue light, respectively. Cyclohexylbenzene is used as theink solvent. As shown in FIG. 3C, the composite inks 32, 33, and 34 arecoated in a pattern by ejecting from the ink jet head at a pitch of211.5 μm in the X direction and at a pitch of 70.5 μm in the Ydirection. In this coating process, another 21 rows of ejection at thesame pitch in both lateral and longitudinal directions in the dummy areaB is performed.

Then, luminous layers 35, 36, and 37 are formed by heat treatment at 80°C. on a hot plate in nitrogen gas for 5 minutes. The luminous layers 35,36, and 37, having a uniform thickness, can thus be formed in theeffectively optical area A.

After forming the luminous layers, a LiF layer 2 nm thick, a Ca layer 20nm thick, and an Al layer 200 nm thick are respectively laminated by aheated vapor deposition in a vacuum so as to form a cathode 38, andfinally, a layer of epoxy resin 39 is formed to perform sealing, asshown in FIG. 3D.

An organic EL device without uneven luminance and uneven chrominance inthe area for the display pixels can thus be manufactured.

Second Embodiment

In the second embodiment shown in FIGS. 4A and 4B, a TFT substrate inwhich a dummy area B is disposed around an effectively optical area A isused, as in the first embodiment. This TFT substrate includes a glasssubstrate 25 and a circuit element portion 26′ having TFTs 26 formed onthe glass substrate. Transparent electrodes 27 made of ITO are formed onthe circuit element portion 26′ and banks including two layers includingSiO₂ banks 28 and polyimide banks 29 are constructed on the circuitlayer 26′ so as to divide the transparent electrodes 27. Thus, displaypixels 42 are formed in the effectively optical area A.

A SiO₂ membrane 28′ extending from the SiO₂ banks is formed in the dummyarea B. The dummy pixels 43 having the same shape as that of the displaypixels 42 and disposed at the same pitch as that at which the displaypixels 42 are disposed are defined by polyimide banks 40. FIG. 4A is apartial cross-sectional view of the right edge portion of the substrate.

The same composite ink 30 for the hole-injection layer as in the firstembodiment is coated in a pattern on both the display pixels 42 and thedummy pixels 43 at a pitch of 70.5 μm, as shown in FIG. 4B. Thehole-injection layers of the display pixels 42 have a uniform thicknessupon completion through the steps of drying and heat treatment as in thefirst embodiment.

In the next process, composite inks for luminous layers includingpolyfluorene materials are coated in a pattern on the display pixels 42and the dummy pixels 43 as in the first embodiment, the luminous layershave a uniform thickness within the display pixels 42 upon completionafter drying. The organic EL device has neither uneven luminance noruneven chrominance in the effectively optical area A including thedisplay pixels 42 upon completion through the steps of cathode formingand sealing.

Third Embodiment

In the third embodiment shown in FIGS. 5A to 5D, a TFT substrate inwhich a dummy area B is disposed around an effectively optical area A,is used, as in the first embodiment. This TFT substrate includes a glasssubstrate 25 and a circuit element portion 26′ having TFTs 26 formed onthe glass substrate, as shown in FIG. 5A. Transparent electrodes 27 madeof ITO are formed on the circuit element portion 26′ and banks includingtwo layers including SiO₂ banks 28 and polyimide-banks 29 areconstructed on the circuit element portion 26′ so as to divide thetransparent electrodes 27. Thus, display pixels 42 are formed in theeffectively optical area A.

On the circuit element portion 26′ in the dummy area B, dummy pixels 44having the same shape and disposed at the same pitch as the displaypixels 42 are only defined by polyimide banks 29. FIG. 5A is a partialcross-sectional view of the right edge portion of the substrate.

The polyimide banks 29 are made to be ink-repelling by atmosphericpressure plasma treatment, as in the first embodiment.

As shown in FIG. 5B, composite ink 30 including the hole-injection layermaterial is coated in a pattern on the display pixels 42 and the dummypixels 43 at a pitch of 70.5 μm, as in the first embodiment. While thecomposite ink 30 of the hole-injection layer material is coated on thetransparent electrodes 27 in the effectively optical area A, thecomposite ink 30 of the hole-injection layer material is coated on thecircuit element portion 26′ in the dummy area B.

Consequently, the solvent is removed by a treatment at room temperaturein a vacuum (1 Torr (133.3 Pa)) for 20 minutes, and then ahole-injection layer 31 is formed, as shown in FIG. 5C, by heattreatment at 200° C. (on a hot plate) in nitrogen gas for 10 minutes.The hole-injection layer 31 having a uniform thickness can thus bemanufactured in the effectively optical area A.

In the next process, three kinds of composite ink, i.e., a composite ink32 for a red luminous layer, a composite ink 33 for a green luminouslayer, and a composite ink 34 for a blue luminous layer, are prepared,and the composite inks 32, 33, and 34 are coated in a pattern byejecting from an ink-jet head at a pitch of 211.5 μm in the X directionand at a pitch of 70.5 μm in the Y direction, respectively, as shown inFIG. 5C. In this coating process, another 21 rows of ejection at thesame pitch in both lateral and longitudinal directions in the dummy areaB is preferably performed.

Then, luminous layers 35, 36, and 37 are formed by heat treatment at 80°C. on a hot plate in nitrogen gas for 5 minutes. The luminous layers 35,36, and 37 having a uniform thickness can thus be formed in theeffectively optical area A.

After forming the luminous layers, a LiF layer 2 nm thick, a Ca layer 20nm thick, and an Al layer 200 nm thick are respectively laminated by aheated vapor deposition in a vacuum so as to form a cathode 38, andfinally, a layer of epoxy resin 39 is formed to provide sealing, asshown in FIG. 5D.

An organic EL device without uneven luminance and uneven chrominance inthe effectively optical area A can thus be manufactured.

Fourth Embodiment

In the fourth embodiment shown in FIGS. 6A to 6D, a TFT substrate inwhich a dummy area B is disposed around an effectively optical area A isused, as in the first embodiment. This TFT substrate includes a glasssubstrate 25 and a circuit element portion 26′ having TFTs 26 formed onthe glass substrate, as shown in FIG. 6A. Transparent electrodes 27 madeof ITO are formed on the circuit element portion 26′ and banks includingtwo layers including SiO₂ banks 28 and polyimide banks 29 areconstructed on the circuit element portion 26′ so as to divide thetransparent electrodes 27. Thus, display pixels 42 are formed in theeffectively optical area A.

On the circuit element portion 26′ in the dummy area B, dummy pixels 45having the same shape and disposed at the same pitch as the displaypixels 42 are formed by laminating the SiO₂ banks 28 and the polyimidebanks 29. FIG. 6A is a partial cross-sectional view of the right edgeportion of the substrate.

Then, as in the first embodiment, the polyimide banks 29 are made to beink-repelling by atmospheric pressure plasma treatment and composite ink30 including the hole-injection layer material is coated in a pattern onthe display pixels 42 and the dummy pixels 45, as shown in FIG. 6B.While the composite ink 30 of the hole-injection layer material iscoated on the transparent electrodes 27 in the effectively optical areaA, the composite ink 30 of the hole-injection layer material is coatedon the circuit element portion 26′ in the dummy area B.

Consequently, the solvent is removed under the same condition as in thefirst embodiment, and then a hole-injection layer 31 is formed, as shownin FIG. 6C, by heat treatment under the same conditions as in the firstembodiment. The hole-injection layer 31 having a uniform thickness canthus be manufactured in the effectively optical area A.

In the next process, a composite ink 32 for a red luminous layer, acomposite ink 33 for a green luminous layer, and a composite ink 34 fora blue luminous layer are prepared and each of the composite inks 32,33, and 34 is coated in a pattern by ejecting from an ink-jet, as shownin FIG. 6C. In this coating process, another 21 rows of ejection at thesame pitch in both lateral and longitudinal directions in the dummy areaB is performed.

Then, luminous layers 35, 36, and 37 are formed by heat treatment at 80°C. on a hot plate in nitrogen gas for 5 minutes. The luminous layers 35,36, and 37 having a uniform thickness can thus be formed in theeffectively optical area A.

After forming the luminous layers, a LiF layer 2 nm thick, a Ca layer 20nm thick, and an Al layer 200 nm thick are respectively laminated byheated vapor deposition in a vacuum so as to form a cathode 38, andfinally, a layer of epoxy resin 39 is formed to provide sealing, asshown in FIG. 6D.

An organic EL device without uneven luminance and uneven chrominance inthe effectively optical area A can thus be manufactured.

Fifth Embodiment

In the fifth embodiment shown in FIGS. 7A to 7D, a TFT substrate inwhich a dummy area B is disposed around an effectively optical area A isused, as in the first embodiment. This TFT substrate includes a glasssubstrate 25 and a circuit element portion 26′ having TFTs 26 formed onthe glass substrate, as shown in FIG. 7A. Transparent electrodes 27 madeof ITO are formed on the circuit element portion 26′ and banks includingtwo layers including SiO₂ banks 28 and polyimide banks 29 areconstructed on the circuit element portion 26′ so as to divide thetransparent electrodes 27. Thus, display pixels 42 are formed in theeffectively optical area A.

On the circuit element portion 26′ in the dummy area B, dummy pixels 46having the same shape and disposed at the same pitch as the displaypixels 42 are formed by laminating the SiO₂ banks 28 and the polyimidebanks 29. The TFTs 26 are not provided in the circuit element portion26′ in the dummy area B. FIG. 7A is partial cross-sectional view of theright edge portion of the substrate.

Then, as in the first embodiment, the polyimide banks 29 are made to beink-repelling by atmospheric pressure plasma treatment and composite ink30 including the hole-injection layer material is coated in a pattern onthe display pixels 42 and the dummy pixels 46, as shown in FIG. 7B.While the composite ink 30 of the hole-injection layer material iscoated on the transparent electrodes 27 in the effectively optical areaA, the composite ink 30 of the hole-injection layer material is coatedon the circuit element portion 26′ in the dummy area B.

Consequently, the solvent is removed under the same conditions as in thefirst embodiment. Then, a hole-injection layer 31 is formed, as shown inFIG. 7C, by heat treatment under the same conditions as in the firstembodiment. The hole-injection layer 31 having a uniform thickness canthus be manufactured in the effectively optical area A.

In the next process, a composite ink 32 for a red luminous layer, acomposite ink 33 for a green luminous layer, and a composite ink 34 fora blue luminous layer are prepared and each of the composite inks 32,33, and 34 is coated in a pattern by ejecting from an ink-jet, as shownin FIG. 7C. In this coating process, another 21 rows of ejection at thesame pitch in both lateral and longitudinal directions in the dummy areaB is preferably performed.

Then, luminous layers 35, 36, and 37 are formed by heat treatment at 80°C. on a hot plate in nitrogen gas for 5 minutes. The luminous layers 35,36, and 37 having a uniform thickness can thus be formed in theeffectively optical area A.

After forming the luminous layers, a LiF layer 2 nm thick, a Ca layer 20nm thick, and an Al layer 200 nm thick are respectively laminated by aheated vapor deposition in a vacuum so as to form a cathode 38, andfinally, a layer of epoxy resin 39 is formed to provide sealing, asshown in FIG. 7D.

An organic EL device without uneven luminance and uneven chrominance inthe effectively optical area A can thus be manufactured.

The dummy pixels 46 include the transparent electrodes 27 and the SiO2banks 28 and the polyimide banks 29 which divide the transparentelectrodes 27. Since the dummy pixels 46 are formed similarly to thedisplay pixels 42, except that the TFTs are not included, the compositeink 30 of the hole-injection layer material coated on the dummy pixels46 can be dried under the same conditions as for the display pixels 42.Thus, the hole-injection layer 31 having a uniform thickness can bemanufactured in the effectively optical area A and an organic EL devicewithout uneven luminance and uneven chrominance in the area for thedisplay pixels can be obtained.

Sixth Embodiment

FIG. 8A is a schematic of a part of the area for the display pixels andthe area for the dummy pixels used in the sixth embodiment. FIG. 8A is aplan view of a substrate and TFT elements are not shown in this view.Circular pixels 50 having diameters of 60 μm are disposed at a pitch of80 μm in a lateral (X) direction and at a pitch of 240 μm in alongitudinal (Y) direction. In a longitudinal direction, dummy bankpixels 51 are disposed between the display pixels at a pitch of 80 μm.Another 30 rows of dummy pixels 52 having the same shape as the displaypixels are disposed all around the effectively optical area at a pitchof 80 μm. The display pixels in the sixth embodiment are defined bylaminated banks including SiO₂ banks 53 and polyimide banks 54 as in theabove embodiments and have similar sectional structure as in the firstand the second embodiment except for the diameter of the pixels and thedisposing pitch.

Composite ink 55 for a hole-injection layer as in the first embodimentis coated in a pattern on the display pixels 50 and the dummy pixels 51and 52 at a pitch of 80 μm, as shown in FIG. 8B. After forming thehole-injection layer as in the first embodiment, a luminous layer isformed by depositing three kinds of composites 56, 57, and 58 for theluminous layer as in the first embodiment at a pitch of 80 μm in alongitudinal direction and a pitch of 240 μm in a lateral direction andby drying them. The composite inks for the luminous layer are depositedin a pattern, as shown in FIG. 8C. Upon completion of further steps ofcathode forming and sealing, the organic EL device shows neither unevenluminance nor uneven chrominance in the effectively optical area.

Seventh Embodiment

FIG. 9A is a schematic of a part of the effectively optical area and thedummy area used in the seventh embodiment. FIG. 9A is a plan view of asubstrate, and TFT elements are not shown in this view. Rectangularpixels 60 which are 50 μm wide and 200 μm long (and having roundedcorners) are disposed at a pitch of 80 μm in a lateral (X) direction andat a pitch of 290 μm in a longitudinal (Y) direction. The gap betweenthe pixels in a lateral direction is 30 μm and the gap between thepixels in a longitudinal direction is 90 μm. Another 30 rows of dummypixels 61 having the same shape as the display pixels are disposed allaround the areas for the display pixels 60 at a pitch of 80 μm and apitch of 290 μm in respective directions. The display pixels 60 aredefined by laminated banks including SiO₂ banks 62 and polyimide banks63 as in the above embodiments and have similar sectional structure asin the first and the second embodiment, except for the size of thepixels and the disposing pitch.

Composite ink 64 for a hole-injection layer as in the first embodimentis coated in a pattern on the display pixels 60 and the dummy pixels 61,and the composite 64 is further coated in a pattern on the middle areasbetween the pixels viewed in a longitudinal direction, as shown in FIG.9B. Upon completion after drying, the hole-injection layer in the pixelsexhibits a uniform thickness. If the composite 64 is not coated on themiddle areas between the pixels viewed in a longitudinal direction, thethickness of the hole-injection layer would become undesirably thick atboth ends of the pixels viewed in a longitudinal direction.

After forming the hole-injection layer, a luminous layer is formed bydepositing three kinds of composites 65, 66, and 67 for the luminouslayer as in the first embodiment at a pitch of 240 μm in a longitudinaldirection and a pitch of 290 μm in a lateral direction. Then compositeinks 65, 66, and 67 for the luminous layer are further coated in apattern on the middle areas between the pixels viewed in a longitudinaldirection, as shown in FIG. 9C, as for the hole-injection layer. Afterdrying, the luminous layer exhibits a uniform thickness within thepixels and among a plurality of pixels. Upon completion through furthersteps of cathode forming and sealing, the organic EL device showsneither uneven luminance nor uneven chrominance in the area for thedisplay pixels.

Eighth Embodiment

FIG. 10A is a plan view of the substrate used in the eighth embodiment.

FIG. 10B is a partial cross-sectional view taken along plane M-M′ inFIG. 10A. As shown in FIGS. 10A and 10B, the substrate 101, on which ahole-injection layer and a luminous layer have not been formed, includesa circuit element portion 103 formed on a glass substrate 102 and aluminous element portion 104 formed on the circuit element portion 103.The luminous element portion 104 includes display pixels and dummypixels, each of which will be further explained below, and is defined byan effectively optical area A including the display pixels and a dummyarea B including dummy pixels and disposed around the effectivelyoptical area A.

The circuit element portion 103 includes a plurality of TFT elements 105formed on the glass substrate 102 and first and second insulatingmembranes 106 and 107 covering the TFT elements 105. The TFT elements105 are disposed in a matrix, to each of which a transparent electrode108 made of ITO is connected. The transparent electrodes 108 are formedon the second insulating membrane 107 at the positions corresponding tothe TFT elements 105 to be connected. The transparent electrodes 108 maybe formed in the shape of a circle, a rectangle, or a rectangle havingrounded corners, in a plan view.

The TFT elements 105 and the transparent electrode 108 are formed onlyin the area corresponding to the effectively optical area A in theluminous element portion 104.

SiO₂ banks 109 and polyimide banks 110 are laminated in the effectivelyoptical area A in the luminous element portion 104. The SiO₂ banks 109and the polyimide banks 110 are disposed between the transparentelectrode 108 whereby apertures 111 surrounding the transparentelectrode 108 are formed.

In the dummy area B, the luminous element portion 104 includes a SiO₂membrane 109′ formed on the second insulating membrane 107 and polyimidebanks 110′ formed on the SiO₂ membrane 109′. The polyimide banks 110′ inthe dummy area B define dummy pixels 111′ having substantially the sameshape as that of the display pixels in the effectively optical area A.

With regard to the quantity of the dummy pixels 111′ formed in the dummyarea B, ten or more dummy pixel sets, each of which includes three kindsof dummy pixels, i.e., a red, a green, and a blue dummy pixel, arepreferably disposed in an area of width X′ along the direction X shownin FIG. 10A. In an area of width Y′ along the direction Y shown in FIG.10A, ten or more of dummy pixel rows, each of which includes a number ofdummy pixels, i.e., a number of red, green, and blue dummy pixels, arepreferably disposed. More preferably, the dummy pixels are disposed soas to equalize width X′ with width Y′. By this disposition, the dryingcondition for the composite ink in the pixels near the border of thedummy area B can be made substantially the same as in the pixels in themiddle of the effectively optical area A. In order to make width X′equal to width Y′, thirty rows of dummy pixels corresponding to rows often dummy pixel sets, each of which includes three kinds of dummypixels, i.e., a red, a green, and a blue dummy pixel, may be formedparallel to the Y direction in the area of width X′, and ten rows ofdummy pixels may be formed parallel to the X direction in the area ofwidth Y′, provided, for example. all the pixels, including both displaypixels and dummy pixels, are disposed at a pitch of 70.5 μm in the Xdirection and at a pitch of 211.5 μm in the Y direction. In thisarrangement, width X′ and width Y′ are substantially equalized becausethe pitch in the Y direction is three times that in the X direction.Although the number of the dummy pixels is not limited, as in the aboveexample, a large number of dummy pixels 111′ is not preferable becausethey may create too wide a peripheral region not relating to display,and consequently unnecessarily enlarge the display module.

The polyimide banks 110 and 110′ are made to be ink-repelling byapplying atmospheric pressure plasma treatment to the substrate 101, asin the first embodiment, and then composite ink including ahole-injection layer material is ejected in a pattern from an ink-jethead onto the display pixels 111 and the dummy pixels 111′. Thecomposite ink of a hole-injection layer material is deposited on thetransparent electrode 108 in the display pixels 111 and is deposited onthe SiO₂ membrane 109′ in the dummy pixels 111′.

A preferred process to eject the composite ink including ahole-injection layer material from an ink-jet head includes, forexample: providing an ink jet head having nozzles in an array whoselength is substantially the same as the width of the luminous elementportion 104 along a lateral direction (X direction in FIG. 10A); andejecting the composite ink while moving the ink-jet head from the bottomin FIG. 10A in the direction of the arrow Y above the substrate 101. Inthis process, the ejection of the composite ink preferably starts in thedummy area B at the bottom of FIG. 10A, proceeds through the effectivelyoptical area A, and ends in the dummy area B at the top of FIG. 10A,i.e., the ejection of the composite ink starts and ends in the dummyarea B. The composite ink in the effectively optical area A driesuniformly because the ejection started in the dummy area B beforeejection in the effectively optical area A.

Consequently, the solvent is removed under the same condition as in thefirst embodiment, and then a hole-injection layer 131 is formed, asshown in FIG. 11A, by heat treatment under the same conditions as in thefirst embodiment.

The dummy pixels 111′ are provided around the effectively optical areaA, to which the steps of ejecting the composite ink and drying as forthe display pixels 111 are also applied. Therefore, the drying conditionfor the display pixels near the border of the dummy area B can be madesubstantially the same as for the display pixels in the middle of theeffectively optical area A, whereby hole-injection layers 131 of auniform thickness can be provided even for the display pixels near theborder of the dummy area B. The hole-injection layers 131 having auniform thickness can thus be manufactured in the entire effectivelyoptical area A.

In the next process, as in the first embodiment, a composite ink for ared luminous layer, a composite ink for a green luminous layer, and acomposite ink for a blue luminous layer are ejected from an ink-head andare deposited on both the display pixels 111 and the dummy pixels 111′in a pattern, and then luminous layers 135, 136, and 137 are formed byheat treatment at 80° C. on a hot plate in nitrogen gas for 5 minutes.The luminous layers 135, 136, and 137 having a uniform thickness canthus be formed in the effectively optical area A, like thehole-injection layers 131.

In this process of forming the luminous layers, the composite inkincluding luminous materials is ejected while moving the ink-jet headfrom the bottom in FIG. 10A in the direction of the arrow Y above thesubstrate 101, as in the process of forming the hole-injection layer,and the ejection of the composite ink preferably starts in the dummyarea B at the bottom of FIG. 10A, proceeds through the effectivelyoptical area A, and ends in the dummy area B at the top of FIG. 10A,i.e., the ejection of the composite ink starts and ends in the dummyarea B. The composite ink including luminous materials dries uniformlyover the entirety of the effectively optical area A.

After forming the luminous layers, a LiF layer 2 nm thick, a Ca layer 20nm thick, and an Al layer 200 nm thick are respectively laminated byheated vapor deposition in a vacuum so as to form a cathode 138, andfinally, a layer of epoxy resin 139 is formed to provide sealing, asshown in FIG. 11B.

An organic EL device without uneven luminance and uneven chrominance inthe effectively optical area A can thus be manufactured.

Ninth Embodiment

FIG. 12 is a plan view of the substrate used in the ninth embodiment. Asshown in FIG. 12, the substrate 201 mainly includes a circuit elementportion (not shown) formed on a glass substrate 202, and a plurality ofluminous element portions 204 formed on the circuit element portion. Thesubstrate 201 shown in FIG. 12 includes 16 luminous element portions 204disposed in a 4-by-4 matrix. Each of the luminous element portions 204is provided with display pixels and dummy pixels (not shown) as in theeighth embodiment, and is defined by an effectively optical area Aincluding the display pixels and a dummy area B including dummy pixelsand disposed around the effectively optical area A.

The structure of the display pixels in the effectively optical area Aand of the dummy pixels in the dummy area B are respectively the same asthat of the display pixels 111 and the dummy pixels 111′ described inthe eighth embodiment. Similarly, the structure of the circuit elementportion (not shown) is the same as that of the circuit element portion103 in the eighth embodiment.

A group C of effectively optical areas including a plurality ofeffectively optical areas A is thus formed on the substrate 201.

The substrate 201 will finally be cut along the dashed lines shown inFIG. 12, and the parts will be separated from each other so as to form16 small substrates. By using this method, a plurality of organic ELdevices can be manufactured from one substrate at one time.

On the substrate 201, another dummy area D is provided around the groupC of effectively optical areas.

With regard to the quantity of the dummy pixels provided in the dummyarea D, ten or more dummy pixel sets, each of which includes three kindsof dummy pixels, i.e., a red, a green, and a blue dummy pixel, arepreferably disposed in an area of width X′ along the direction X shownin FIG. 12. In an area of width Y′ along the direction Y shown in FIG.12, ten or more dummy pixel rows, each of which consists of a number ofdummy pixels, i.e., a number of red, green, and blue dummy pixels, arepreferably disposed.

Polyimide banks fanned on the substrate 201 is made to be ink-repellingas in the eighth embodiment. Then, composite ink including ahole-injection layer material is ejected in a pattern from an ink-jethead onto the display pixels and the dummy pixels.

A preferred process to eject the composite ink including ahole-injection layer material from an inkjet head includes, for example:providing an ink jet head having nozzles in an array whose length issubstantially the same as the width of a single luminous element portion204 along a lateral direction (X direction in FIG. 12); and ejecting thecomposite ink while moving the ink-jet head from the bottom in FIG. 12in the direction of the arrow Y to the top. The width of the ink-jethead is not limited as in this example, and it may also be chosen so asto be a multiple of the width of a single luminous element portion 204.

In this process, the traced path of the ink-jet head H may be as shownin FIG. 13A in which the ink-jet head H moves upwardly in view of FIG.13A, moves diagonally and downwardly in an idling state, and movesupwardly again, or may be as shown in FIG. 13B in which the ink jet headH moves upwardly in view of FIG. 13B, moves laterally in an idlingstate, and moves downwardly.

In both of the above ways, the composite ink is sequentially ejectedonto the dummy areas D and B, the effectively optical area A, the dummyareas B and D, the dummy areas D and B, the effectively optical area A,. . . , and the dummy areas B and D, i.e., the ejection of the compositeink starts and ends in the dummy area D.

Alternatively, the process may include, as in the eighth embodiment:providing an ink-jet head having nozzles in an array whose length issubstantially the same as the width of the group C of effectivelyoptical areas along a lateral direction (X direction in FIG. 12); andejecting the composite ink while moving the ink-jet head from the bottomin FIG. 12 in the direction of the arrow Y to the top above the luminouselement portions 204. In this case, the composite ink is sequentiallyejected onto the dummy areas D and B, the effectively optical area A,the dummy areas B and D, i.e., the ejection of the composite ink startsand ends in the dummy area D.

In all of the cases described above, the composite ink in theeffectively optical area A dries uniformly because the ejection startedin the area D for the dummy pixels before ejection in the effectivelyoptical area A.

In the cases shown in FIGS. 13A and 13B in which the ink-jet head tracesa reciprocating path, the ejection of the composite ink in theeffectively optical area A is fairly stable, even if the state of theink contained in the ink-jet head changes during an idling travel,because the ejection has started in the area D for the dummy pixelsbefore ejecting onto the effectively optical area A, and the compositeink is always ejected onto the area D for the dummy pixels after idlingof the ink-jet head.

Consequently, the solvent of the composite ink of a hole-injection layermaterial is removed and a hole-injection layer 131 is formed by heattreatment, under the same conditions as in the first embodiment.

The dummy pixels included in the dummy area B are provided around theeffectively optical area A and these dummy pixels are further surroundedby other dummy pixels included in the dummy area D. Therefore, thedrying condition for the display pixels near the border of the dummyarea B can be made substantially the same as for the display pixels inthe middle of the effectively optical area A, whereby hole-injectionlayers of a uniform thickness can be provided in the entirety of theeffectively optical area A even for the display pixels near the borderof the dummy area B.

The hole-injection layers having a uniform thickness can thus bemanufactured, even in a case in which a number of display devices aremanufactured from a single substrate because the dummy area D isprovided around the group C of the effectively optical areas.

In the next process, as in the first embodiment, a composite ink for ared luminous layer, a composite ink for a green luminous layer, and acomposite ink for a blue luminous layer are ejected from an ink jet headand are deposited in both the effectively optical area and the dummyarea in a pattern, and then the red, green, and blue luminous layers areformed by heat treatment. The luminous layers having a uniform thicknesscan thus be formed in the effectively optical area A, like thehole-injection layers.

In this process of forming the luminous layers, the composite ink ispreferably ejected while moving the ink-jet head as shown in FIG. 13A or13B, as in the process of forming the hole-injection layer, and theejection of the composite ink preferably starts and ends in the dummyarea D, whereby, the composite ink dries uniformly over the entirety ofthe effectively optical area A.

After forming the luminous layers, a LiF layer 2 nm thick, a Ca layer 20nm thick, and an Al layer 200 nm thick are respectively laminated byheated vapor deposition in a vacuum so as to form a cathode, andfinally, a layer of epoxy resin is formed to provide sealing.

An organic EL device without uneven luminance and uneven chrominance inthe effectively optical area A can thus be manufactured.

Although a high molecular material is used for the organic EL layer inthe foregoing embodiments, a low molecular material may be used instead.The organic EL layer is preferably formed by a vapor deposition methodusing a mask 71, as shown in FIG. 14, when a low molecular material isused therefor. An organic EL device according to the present inventioncan be manufactured by using a mask having a set of aperturescorresponding to an effectively optical area E and another set ofapertures corresponding to an area other than the effectively opticalarea E, i.e., a dummy area F. Uniform organic EL layers can be formed inthe entirety of the effectively optical area by also providing the dummyarea in the vapor deposition method.

Tenth Embodiment

Examples of electronic devices including an organic EL devicemanufactured by using a method according to any one of the first toninth embodiments described above will be explained below.

FIG. 15A is a perspective view of an example of a portable telephone. InFIG. 15A, reference numeral 600 indicates a body of the portabletelephone, and reference numeral 601 indicates a display portionincluding any one of the organic EL devices described above.

FIG. 15B is a perspective view of an example of a portable informationprocessor, such as a word processor and a personal computer. In FIG.15B, reference numeral 700 indicates an information processor, referencenumeral 701 indicates an input device, such as a keyboard, referencenumeral 703 indicates a body of the information processor, and referencenumeral 702 indicates a display portion including any one of the organicEL devices described above.

FIG. 15C is a perspective view of an example of a watch. In FIG. 15C,reference numeral 800 indicates a body of the watch, and referencenumeral 801 indicates a display portion including any one of the organicEL devices described above.

Each of the electronic devices shown in FIGS. 15A to 15C includes adisplay portion including any one of the organic EL devices describedabove, and consequently has the same advantages as that of the organicEL device manufactured using a method according to any one of the firstto ninth embodiments described above. Therefore, these electronicdevices will exhibit excellent display performance.

As described above, in a method for manufacturing an organic EL deviceusing an inkjet method to eject and coating an organic EL material on asubstrate to form an organic EL layer, a dummy coating area is providedaround an area for display pixels, and ink droplets are disposed at aconstant pitch in the area for display pixels, according to the presentinvention. The organic EL material solution coated on the effectivelyoptical area dries uniformly and a uniform display device without unevenluminance and uneven chrominance within a pixel or among a plurality ofpixels in the effectively optical area can be obtained.

What is claimed is:
 1. An organic electroluminescent device comprising:a substrate that has an effectively optical area for display and a dummyarea outside the effectively optical area not for display; a bank thatis disposed in the effectively optical area and the dummy area; a firstelectrode that is disposed in the effectively optical area; a secondelectrode that is disposed in the effectively optical area and the dummyarea, the second electrode opposed the first electrode; a first luminouslayer that is disposed between the first electrode and the secondelectrode in the effectively optical area, the first luminous layerincluding a light emitting material; and a second luminous layer that isdisposed in the dummy area, the second luminous layer including thelight emitting material and being different from the first luminouslayer, the second electrode covering the bank, the first luminous layer,and the second luminous layer in the effectively optical area and thedummy area.
 2. An organic electroluminescent device comprising: asubstrate that has an effectively optical area for display and a dummyarea outside the effectively optical area not for display; a bank thatis disposed in the effectively optical area and the dummy area; a firstelectrode that is disposed in the effectively optical area; a secondelectrode that is disposed in the effectively optical area and the dummyarea, the second electrode opposed the first electrode; a first luminouslayer that is disposed between the first electrode and the secondelectrode in the effectively optical area, the first luminous layerincluding a light emitting material; and a second luminous layer that isdisposed on the bank in the dummy area, the second luminous layerincluding the light emitting material and being different from the firstluminous layer.
 3. The organic electroluminescent device according toclaim 1, wherein the first electrode not being disposed in the dummyarea.
 4. The organic electroluminescent device according to claim 1,further comprising a transistor being electrically connected to thefirst electrode, the transistor disposed in the effectively optical areaand not disposed in the dummy area.
 5. The organic electroluminescentdevice according to claim 1, wherein the first electrode not beingdisposed in the dummy area.